Typical golf club sets include three types of clubs called “woods,” “irons,” and “putters” which are well known in the art. Woods, also referred to as “drivers” and “fairway woods”, are generally used to hit the ball as far as possible. Irons are used to hit the ball a given or specific distance dictated by the position of the ball on the course. These types of clubs, including wedges, are also referred to as “controlled distance clubs”. Putters are used to hit the ball short distances on a green into the hole.
While the flight distance of a ball hit by a golf club depends on a golfer's skills, the a) ball direction, b) flight distance and c) trajectory ultimately depend on the efficiency of the golf club itself.
The shaft design, length, and the club head loft help determine the playing characteristics of the club. As the shaft length increases, speed of the club head increases and on impact with the ball, the ball travels farther. As the shaft length decreases, the speed of the impact of the club head on the ball decreases, causing the ball to travel a shorter distance. In addition, as the loft increases, the potential arc or trajectory of the ball in flight also increases. As the ball trajectory increases, the potential ball distance decreases. Conversely, as the loft decreases, the potential arc or trajectory of the ball in flight also decreases. As the ball trajectory decreases, the more the potential ball distance increases.
Typical golf club sets consist of clubs having different lofts, lies and lengths. Throughout the set, as the shaft length increases, the loft and lie angles decrease. Nominally, the golf club shaft lengths increase or decrease by predetermined increments between adjacent clubs of the set. For a set of irons, the shaft stiffness generally increases from the long irons to the short irons, i.e., the short irons will have more shaft stiffness than the long irons due to the length of the club and weight of the head.
Golf club shafts are designed to have a butt section and a tip section interconnected by a tapered section, wherein the butt section has a larger outer diameter than the tip section. The butt and tip sections typically have a constant outer diameter throughout their length. The outer diameter is reduced from the butt to the tip by utilizing a tapered section.
The prior art shafts have tapered sections which are substantially the same length throughout the entire set of golf clubs. By having a relatively shorter tip section relative to the butt section, an increase in the overall shaft stiffness is obtained. Thus, a set of iron shafts, using prior art design techniques, uses different relative tip and butt lengths while maintaining an equal tapered section length to generate a progressive stiffness throughout the set.
In view of the present invention, the disadvantages of a constant tapered section length throughout the set of clubs are having reduced energy transfer, poor feel perceived by the golfer, less ball flight distance, greater ball flight dispersion, and less golf club stability.